Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.

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IPadOS 17 external camera exposure
I'm developing iPad app that will be mostly dedicated for certain external camera for visually impaired people. The linux UVC api (e.g. using guvcview) allows to enable automatic exposure for the camera. IOs api "isExposureModeSupported" unfortunately returns false for any of the exposure modes. Is it a bug? Or perhaps AVFoundation doesn't support UVC exposure yet?
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559
Jul ’25
Is it possible to retrieve EXIF metadata from PHAsset without downloading photos (even if offloaded to iCloud Photo Library)?
iOS (Official) Photos app can display some EXIF-related metadata (e.g. camera and lens info, ISO, shutter speed, F-number) even when photos are offloaded to iCloud and the device is not connected to internet (e.g. airplane mode). However, with the Photos.framework, we need to download photos to retrive those metadata (which means it will not work with airplane mode). I tried the following methods, but none of those worked when photos were offloaded to iCloud and the device was in airplane mode: Requesting data with PHImageManager.default().requestImageDataAndOrientation Result: It does not return Data if the photo is not stored locally on the device, even with options.deliveryMode = .fastFormat Converting PHAsset#localIdentifier to an AssetsLibrary.framework URL (assets-library://asset/...) (I am aware that AssetsLibrary.framework is deprecated, but this was just a test.) Result: If PHImageManager does not returns Data, ALAsset#defaultRepresentation().metadata() returns an empty NSDictionary
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599
Nov ’24
CheckError.swift:CheckError(_:):211:kAudioUnitErr_InvalidParameter (CheckError.swift:CheckError(_:):211)
I'm getting this error when I launch my application on the iPhone 14 Pro via Xcode. Everything builds OK. I"m using the audio kit plugin and Sound Pipe Audiokit. The error starts as soon as I start the app and will carry on repeatedly. I have background processing turned on as I'd like the sounds to play when the phone is locked via the headphones. I can't find anything online about this error. None of my catches are printing anything in the logs either. So I don't know if this is just something that pops up repeatedly or whether there is something fundamentally wrong. private func setupAudioSession() { do { let session = AVAudioSession.sharedInstance() try session.setCategory(.playback, mode: .default, options: [.mixWithOthers]) try session.setActive(true, options: .notifyOthersOnDeactivation) } catch { errorMessage = "Failed to set up audio session: (error.localizedDescription)" print(errorMessage ?? "") } } // MARK: - Background Task Handling private func setupBackgroundTaskHandling() { // Handle app entering background notificationObservers.append( NotificationCenter.default.addObserver( forName: UIApplication.didEnterBackgroundNotification, object: nil, queue: .main, using: { [weak self] _ in // Safely unwrap self guard let self = self else { return } self.handleBackgroundTransition() } ) ) I'm not sure if this is the code causing the issue. Any help would be gratefully appreciated. This is my first app I'm working on .
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Apr ’25
Darkish line on Photos app. Not a hardware issue.
Hey, There's like this darkish line on my iPhone and iPad when I open the Photos app. This scared the ding dong out of me the first time I saw it but then I realized in was a software issue when it disappeared as I swiped up to close the app. It's really weird because it's extremely faint but I can't seem to catch it in screenshots. I know for a fact this is a software issue because it doesn't show up in any other apps. It also changes from horizontal to vertical depending on how I turn my iPhone. Can everyone please just check your own iPhone or iPad to make sure I'm not the only one? I'm on the 18.2 developer beta by the way. Thanks!
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Nov ’24
Multiview HLS with HDR
I have an HDR10+ encoded video that if loaded as a mov plays back on the Apple Vision Pro but when that video is encoded using the latest (1.23b) Apple HLS tools to generate an fMP4 - the resulting m3u8 cannot be played back in the Apple Vision Pro and I only get back a "Cannot Open" error. To generate the m3u8, I'm just calling mediafilesegmenter (with -iso-fragmented) and then variantplaylistcreator. This completes with no errors but the m3u8 will playback on the Mac using VLC but not on the Apple Vision Pro. The relevant part of the m3u8 is: #EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=40022507,BANDWIDTH=48883974,VIDEO-RANGE=PQ,CODECS="ec-3,hvc1.1.60000000.L180.B0",RESOLUTION=4096x4096,FRAME-RATE=24.000,CLOSED-CAPTIONS=NONE,AUDIO="audio1",REQ-VIDEO-LAYOUT="CH-STEREO" {{url}} Has anyone been able to use the HLS tools to generate fMP4s of MV-HEVC videos with HDR10?
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1k
Feb ’25
Creating an initial Now Playing state of paused - impossible?
I am working on an app which plays audio - https://youtu.be/VbAfUk_eYl0?si=nJg5ayy2faWE78-g - and one of the features is, on restart, if you had paused playback of a file at the time the app was previously shut down (or were playing one at the time of shutdown), the paused state and position in the file is restored exactly as it was, on restart. The functionality works. However, it seems impossible to get the "now playing" information in iOS into the right state to reflect that via the MediaPlayer API. On restart, handlers are attached to the play/pause/togglePlayPause actions on MPRemoteCommandCenter.shared(), and the map of media info is updated on MPNowPlayingInfoCenter.default().nowPlayingInfo. What happens is that iOS's media view shows the audio as playing and offers a pause button - even though the play action is enabled and the pause action is disabled. Once playback has been initiated (my workaround is to have the pause action toggle the play state, since otherwise you wouldn't be able to initiate playback from controls in a car without initiating it once from a device first). I've created a simplified white-noise-player demo to illustrate the problem - simply build and deploy it, and then start the app, lock your device and look at the playback controls on the lock screen. It will show a pause button - same behavior I've described. https://github.com/timboudreau/ios-play-pause-demo I've tried a few things to narrow down the source of the issue - for example, thinking that not MPNowPlayingInfoPropertyPlaybackProgress and MPMediaItemPropertyPlaybackDuration might be the culprit (since the system interpolates elapsed time and it's recommended to update those properties infrequently) on startup might do the trick, but the result is the same, just without a duration or progress shown. What governs this behavior, and is there some way to explicitly tell the media player API your current state is paused?
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Apr ’25
Reference White Calculation for HDR Video Rendering in Metal
Our multimedia application Boinx FotoMagico displays media files of various kinds with a Metal rendering engine. At the moment we still use .bgra8Unorm pixel format and sRGB color space and only render in SDR, which is increasingly a problem, as much of the video content is HDR nowadays (e.g. videos shot on an iPhone). For that reason we would like to switch to EDR rendering with .rgba16Float pixel format and extendedLinearDisplayP3 color space. We have already worked out how to do this for HDR image files, but still have a technical problem when rendering HDR video files. We are using AVFoundation to get the video frames as CVPixelBuffers and convert them to MTLTexture using a CVMetalTextureCache. MTLTextures are then further processed in various compute shaders before being rendered to screen. However the pixel values in the texture are not what we expected. Video frames appear too bright/overexposed. In WWDC21 session "Explore HDR rendering with EDR" Ken Greenebaum mentioned: “AVFoundation does not presently decode HDR formats, such as HDR10, to EDR. Consequently, these need to be adapted for use with EDR rendering. This conversion is straightforward and involves two steps. First, converting to linear light by applying the inverse transfer function. And second, dividing by the medium's reference white.” https://developer.apple.com/videos/play/wwdc2021/10161?time=1498 However, the session does not explain, how to get or calculate the correct value for "reference white". We could not find any relevant info on the web. This is why we need DTS assistance. We need the code that calculates the correct value for reference white for any kind of video, whether it is SDR or HDR, and regardless of codec and encoding. I assume that Ken Greenebaum is the best Apple engineer to ask in this case, because he recorded most of the EDR related WWDC sessions in recent years? We have written a small test app that renders a short sample video (HLG encoding). The window contains two views. The upper view uses an AVPlayerLayer and renders the video natively just like QuickTime Player. The video content looks correct here. BTW, the window background is SDR white, so that bright EDR pixels can be clearly identified, e.g. the clouds just above the mountains in the upper left corner of the sample video. You may need to lower display brightness a bit if these clouds do not appear brighter than the white window background. The bottom view uses a CAMetalLayer and low-level Metal rendering. The CVPixelBuffers we receive from AVFoundation still need to be scaled down so that SDR reference white reaches pixel value 1.0. Entering a value of 9.0 to 10.0 for reference white in the text field makes it look about right on my Studio Display. But that is just experimental for this sample video file. We need code to calculate the correct value for reference white for any kind of video file! We have a couple of questions: SDR videos should probably use 1.0 as reference white, as their encoded pixel values can already be used as is? Is this assumption correct? Different video encoding of HDR video (HLG, PQ, etc) will probably lead to different values for reference white? Is the value for reference white constant throughout a video, or can it vary over time, either scene by scene, or even frame by frame? If it can vary, does the CVPixelBuffer of the current video frame contain all the necessary metadata to calculate the correct value? Does the NSScreen.maximumExtendedDynamicRangeColorComponentValue also influence the reference white value? The attached sample project is structured in a way that the only piece of code that needs to be modified is the ViewController.sdrReferenceWhiteValue() function. Please read the comments and the #warning in this function. This is where the code for calculating the reference white value should be inserted. Here is the download link for the sample project: https://www.dropbox.com/scl/fi/4w5gmftav5xhbixu9u6pb/HDRMetalTest.zip?rlkey=n8cm02soux3rx03vplgo6h1lm&dl=0
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Feb ’25
[Request] Support for Spotify-like Audio Analysis API for Apple Music.
Hi, I have been working on a project that enables users to listen to their favorite music using a streaming service, which so far was Spotify. The app had a programmable 3D/2D interface with the ability to connect to devices in your home and have them react to music. As of September 2024, Spotify decomissioned their Audio Analysis API. I have seen other posts mention playing Apple Music through AVFoundation, which would break DRM and so it’s not supported. However, the Spotify Audio Analysis API does not allow for a full frequency reconstruction. It is entirely temporal data on beats, kicks, loudness, and timbre changes, which themselves are operators on the spectral data from the FFT. It would be very useful for the developer community if we get the ability to do this and it will probably Apple Music among developers and those who use their apps a lot more. Would love to hear your thoughts about this and Happy New Year!
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Dec ’24
Audio clipping - macOS Tahoe 26 - Beta 5
I was testing audio playback from YouTube in Safari, and the sound was clipping heavily. At first, I thought it might be due to the poor quality of my small sound system. However, when I took a screenshot and the screenshot sound effect itself produced a loud clipping noise, it became clear that this is not a mechanical problem with my speakers, nor an issue specific to YouTube or Safari. This appears to be a system-wide audio issue in macOS Tahoe 26 - Beta 5.
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267
Aug ’25
How to use the SpeechDetector Module
I am trying to use SpeechDetector Module in Speech framework along with SpeechTranscriber. and it is giving me an error Cannot convert value of type 'SpeechDetector' to expected element type 'Array.ArrayLiteralElement' (aka 'any SpeechModule') Below is how I am using it let speechDetector = Speech.SpeechDetector() let transcriber = SpeechTranscriber(locale: Locale.current, transcriptionOptions: [], reportingOptions: [.volatileResults], attributeOptions: [.audioTimeRange]) speechAnalyzer = try SpeechAnalyzer(modules: [transcriber,speechDetector])
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Aug ’25
After iPadOS 26 beta and iOS 26 beta, AVCaptureMetadataOutput no longer detects Face on some devices.
I'm creating an app that uses AVCaptureSession to pass camera input to AVCaptureMetadataOutput type set [metaout setMetadataObjectTypes:@[AVMetadataObjectTypeFace]] and scan Face. After updating to OS 26 Beta2 and iOS 26 Beta2, an issue has occurred where the delegate method of AVCaptureMetadataOutputObjectsDelegate is not called on some devices. The following devices are experiencing this issue. iPad (9th Gen) iPad air (4th Gen) iPhone 15 This issue has not occur on any other devices I have. I tried running the AVFoundation sample code on the Apple Developer site on the above device. The same problem still occurs. https://developer.apple.com/documentation/avfoundation/capture_setup/avcambarcode_detecting_barcodes_and_faces Are any additional settings required after OS 26 beta and iOS 26 beta? Or is there some problem on the OS side?
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107
Jul ’25
I cannot revoke Apple Fairplay Streaming certificate
We move to another streaming service and need to deliver a ASK, .PEM &key, and CRT to enable DRM. Now the issue is that we don't have that information anymore. Most logical would be to revoke the current certificate and create a new one. Unfortunately for Fairplay Streaming Certificates there is no revoke button. We asked developer support who isn't able to help. We then did a request to revoke as described in article 2.7 of the Apple Developer Program License Agreement. They can only do this when the certificate is compromised. So now we are stuck. Anyone out there who had the same issue and found a solution? Your help is much appreciated.
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Jan ’25
PushToTalk
Using the PushToTalk library, call requestBeginTransmitting (channelUUID: UUID) on a Bluetooth device and then use the PTChannelManagerial Delegate proxy method channelManager:(PTChannelManager *)channelManager didActivateAudioSession:(AVAudioSession *)audioSession Start recording sound inside. Completed recording
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AVSpeechSynthesizer - just not working on 15.1.1
So get a swift file and put this in it import Foundation import AVFoundation let synthesizer = AVSpeechSynthesizer() let utterance = AVSpeechUtterance(string: "Hello, testing speech synthesis on macOS.") if let voice = AVSpeechSynthesisVoice(identifier: "com.apple.voice.compact.en-GB.Daniel") { utterance.voice = voice print("Using voice: \(voice.name), \(voice.language)") } else { print("Daniel voice not found on macOS.") } synthesizer.speak(utterance) I get no speech output and this log output Error reading languages in for local resources. Error reading languages in for local resources. Using voice: Daniel, en-GB Program ended with exit code: 0 Why? and whats with "Error reading languages in for local resources." ?
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939
Dec ’24
iOS 16 MusicKit - Artwork has no background or text colors
Hello, I'm new to the Swift MusicKit API and am starting with the implementation in iOS 16. I'm getting stuck on an issue where there is no background or text color associated with the Artwork object. Is this something you have to make an additional property request for, and if so, how do you do that? var catalogSearch = MusicCatalogResourceRequest<Album>(matching: \.id, equalTo: item.id) let catalogResponse = try await request.response() guard let firstItem = catalogResponse.items.first else { return } In this example, firstItem.artwork only contains the url and what look like incorrect max width/height values. here's a printout of firstItem.artwork Optional(Artwork(   urlFormat: "musicKit://artwork/library/5F37858D-F46B-4F12-BA67-40FA8DD63D87/{w}x{h}?at=item&fat=&id=7718670444435992305&lid=5F37858D-F46B-4F12-BA67-40FA8DD63D87&mt=music&aat=Music122/v4/37/25/f5/3725f515-249f-7b91-77bb-f479cd48201c/22UMGIM32254.rgb.jpg", maximumWidth: 0, maximumHeight: 0 ))
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Mar ’25
Constituent active device switching very slow on iPhone 16 Pro Models on focus changes
Hi all, we are in the business of scanning documents and barcodes with the camera system of mobile devices. Since there is a wide variety of use cases, from scanning tiniest barcodes and small business cards to scanning barcodes or large documents from far distances we preferably rely on the triple camera devices, if available, with automatic constituent device switching. This approach used to be working perfectly fine. Depending on the zoom level (we prefer to use an initial zoom value of 2.0) and the focusing distance the iPhone Pro models switched through the different camera systems at light speed: from ultra-wide to wide, tele and back. No issues at all. Unfortunately the new iPhone 16 Pro models behave very different when it comes to constituent device switching based on focus distance. The switching is slow and sometimes it does not happen at all when the focusing distance changes. Especially when aiming for a at a distant object for a longer time and then aiming at a very close object that is maybe 2" away. The iPhone 15 Pro here always switches immediately to the ultra-wide camera, while the iPhone 16 Pro takes at least 2-3 seconds, in rare cases up to 10 seconds and sometimes forever to switch to the ultra-wide camera. Of course we assumed that our code is responsible for these issues. So we experimented with restricting the devices and so on. Then we stripped more and more configuration code but nothing we tried improved the situation. So we ended up writing a minimal example app that demonstrates the problem. You can find the code below. Execute it on various iPhones and aim at far distance (> 10 feet) and then quickly to very close distance (<5 inches). Here is a list of devices and our test results: iPhone 15 Pro, iOS 17.6: very fast and reliable switching iPhone 15 Pro, iOS 18.1: very fast and reliable switching iPhone 13 Pro Max, iOS 15.3: very fast and reliable switching iPhone 16 (dual-wide camera), iOS 18.1: very fast and reliable switching iPhone 16 Pro, iOS 18.1: slow switching, unreliable iPhone 16 Pro Max, iOS 18.1: slow switching, unreliable Questions: Does anyone else have seen this issue? And possibly found a workaround? Is this behaviour intended on iPhone 16 Pro models? Can we somehow improve the switching speed? Further the iPhone 16 Pro models also show a jumping preview in the preview layer when they switch the constituent active device. Not dramatic, but compared to the other phones it looks like a glitch. Thank you very much! Kind regards, Sebastian import UIKit import AVFoundation class ViewController: UIViewController { var captureSession : AVCaptureSession! var captureDevice : AVCaptureDevice! var captureInput : AVCaptureInput! var previewLayer : AVCaptureVideoPreviewLayer! var activePrimaryConstituentToken: NSKeyValueObservation? var zoomToken: NSKeyValueObservation? override func viewDidLoad() { super.viewDidLoad() } override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) checkPermissions() setupAndStartCaptureSession() } func checkPermissions() { let cameraAuthStatus = AVCaptureDevice.authorizationStatus(for: AVMediaType.video) switch cameraAuthStatus { case .authorized: return case .denied: abort() case .notDetermined: AVCaptureDevice.requestAccess(for: AVMediaType.video, completionHandler: { (authorized) in if(!authorized){ abort() } }) case .restricted: abort() @unknown default: fatalError() } } func setupAndStartCaptureSession() { DispatchQueue.global(qos: .userInitiated).async{ self.captureSession = AVCaptureSession() self.captureSession.beginConfiguration() if self.captureSession.canSetSessionPreset(.photo) { self.captureSession.sessionPreset = .photo } self.captureSession.automaticallyConfiguresCaptureDeviceForWideColor = true self.setupInputs() DispatchQueue.main.async { self.setupPreviewLayer() } self.captureSession.commitConfiguration() self.captureSession.startRunning() self.activePrimaryConstituentToken = self.captureDevice.observe(\.activePrimaryConstituent, options: [.new], changeHandler: { (device, change) in let type = device.activePrimaryConstituent!.deviceType.rawValue print("Device type: \(type)") }) self.zoomToken = self.captureDevice.observe(\.videoZoomFactor, options: [.new], changeHandler: { (device, change) in let zoom = device.videoZoomFactor print("Zoom: \(zoom)") }) let switchZoomFactor = 2.0 DispatchQueue.main.async { self.setZoom(CGFloat(switchZoomFactor), animated: false) } } } func setupInputs() { if let device = AVCaptureDevice.default(.builtInTripleCamera, for: .video, position: .back) { captureDevice = device } else { fatalError("no back camera") } guard let input = try? AVCaptureDeviceInput(device: captureDevice) else { fatalError("could not create input device from back camera") } if !captureSession.canAddInput(input) { fatalError("could not add back camera input to capture session") } captureInput = input captureSession.addInput(input) } func setupPreviewLayer() { previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) view.layer.addSublayer(previewLayer) previewLayer.frame = self.view.layer.frame } func setZoom(_ value: CGFloat, animated: Bool) { guard let device = captureDevice else { return } let maxZoom: CGFloat = captureDevice.maxAvailableVideoZoomFactor let minZoom: CGFloat = captureDevice.minAvailableVideoZoomFactor let zoomValue = max(min(value, maxZoom), minZoom) let deltaZoom = Float(abs(zoomValue - device.videoZoomFactor)) do { try device.lockForConfiguration() if animated { device.ramp(toVideoZoomFactor: zoomValue, withRate: max(deltaZoom * 50.0, 50.0)) } else { device.videoZoomFactor = zoomValue } device.unlockForConfiguration() } catch { return } } }
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Dec ’24
How can third-party iOS apps obtain real-time waveform / spectrogram data for Apple Music tracks (similar to djay & other DJ apps)?
Hi everyone, I’m working on an iOS MusicKit app that overlays a metronome on top of Apple Music playback. To line the clicks up perfectly I’d like access to low-level audio analysis data—ideally a waveform / spectrogram or beat grid—while the track is playing. I’ve noticed that several approved DJ apps (e.g. djay, Serato, rekordbox) can already: • Display detailed scrolling waveforms of Apple Music songs • Scratch, loop or time-stretch those tracks in real time That implies they receive decoded PCM frames or at least high-resolution analysis data from Apple Music under a special entitlement. My questions: 1. Does MusicKit (or any public framework) expose real-time audio buffers, FFT bins, or beat markers for streaming Apple Music content? 2. If not, is there an Apple program or entitlement that developers can apply for—similar to the “DJ with Apple Music” initiative—to gain that deeper access? 3. Where can I find official documentation or a point of contact for this kind of request? I’ve searched the docs and forums but only see standard MusicKit playback APIs, which don’t appear to expose raw audio for DRM-protected songs. Any guidance, links or insider tips on the proper application process would be hugely appreciated! Thanks in advance.
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How can third-party iOS apps obtain real-time waveform / spectrogram data for Apple Music tracks (similar to djay & other DJ apps)?
Hi everyone, I’m working on an iOS MusicKit app that overlays a metronome on top of Apple Music playback. To line the clicks up perfectly I’d like access to low-level audio analysis data—ideally a waveform / spectrogram or beat grid—while the track is playing. I’ve noticed that several approved DJ apps (e.g. djay, Serato, rekordbox) can already: • Display detailed scrolling waveforms of Apple Music songs • Scratch, loop or time-stretch those tracks in real time That implies they receive decoded PCM frames or at least high-resolution analysis data from Apple Music under a special entitlement. My questions: 1. Does MusicKit (or any public framework) expose real-time audio buffers, FFT bins, or beat markers for streaming Apple Music content? 2. If not, is there an Apple program or entitlement that developers can apply for—similar to the “DJ with Apple Music” initiative—to gain that deeper access? 3. Where can I find official documentation or a point of contact for this kind of request? I’ve searched the docs and forums but only see standard MusicKit playback APIs, which don’t appear to expose raw audio for DRM-protected songs. Any guidance, links or insider tips on the proper application process would be hugely appreciated! Thanks in advance.
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